Abnormal neural response to phonological working memory demands in persistent developmental stuttering.

Area of Science:

• Neuroscience
• Cognitive Psychology
• Speech and Language Sciences

Background:

• Persistent developmental stuttering is often viewed as a motor disorder, but cognitive theories suggest underlying deficits in cognitive skills.
• Working memory (WM), crucial for speech production, is implicated as a potential factor in stuttering.
• Understanding the neurophysiological basis of WM in stuttering is essential.

Purpose of the Study:

• To investigate the brain mechanisms associated with phonological working memory (WM) in adults who stutter (PWS) compared to controls.
• To determine if WM deficits contribute to the neurophysiological underpinnings of stuttering.
• To explore the neural correlates of phonological WM tasks in PWS.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to examine brain activity during a phonological WM task.
• Participants included adults who stutter and age- and sex-matched controls.
• Analysis focused on identifying differences in brain activation patterns and neural connectivity.

Main Results:

• Adults who stutter exhibited a right-lateralized compensatory mechanism related to a deficit in the rehearsal process.
• Neural disconnections were observed, associated with central executive dysfunction in PWS.
• These neural abnormalities in phonological WM were present regardless of memory load.

Conclusions:

• This study provides the first evidence of atypical neural responses to phonological working memory in adults who stutter.
• Findings suggest that working memory deficits and associated neural abnormalities are integral to the neurophysiological basis of stuttering.
• These results challenge purely motor-based explanations and highlight cognitive-neurological factors in stuttering etiology.